Apple's senior vice president of hardware engineering Bob Mansfield is retiring, the company said today.

Mansfield, who has been with Apple since 1999, will be replaced by Dan Riccio, Apple's current vice president of iPad hardware engineering.

"Bob has been an instrumental part of our executive team, leading the hardware engineering organization and overseeing the team that has delivered dozens of breakthrough products over the years," Apple CEO Tim Cook said in a statement. "We are very sad to have him leave and hope he enjoys every day of his retirement."

Apple says the transition from Mansfield to Riccio will take place "over several months."

Mansfield replaced the outgoing Mark Papermaster in 2010, and has since gone on to become one of the public faces of the company in its promotional videos. He is often seen describing the technical ins and outs of the company's latest products. Before Apple, Mansfield was at Silicon Graphics, then at Raycer graphics, a company Apple acquired.

Mansfield's departure is the first from Apple's executive team since Tim Cook took over as CEO last August. Prior to that, retail chief Ron Johnson announced plans to leave to become the chief executive at retail chain J.C. Penney, a spot that's since been filled by John Browett. Before Johnson, it was the departure of Bertrand Serlet, Apple's senior vice president of Mac software engineering.

The retirement isn't the only one among Apple's staff today. In an SEC filing posted earlier today, Apple said Betsy Rafael, who is currently a company VP, corporate controller, and principal accounting officer would retire from the company on October 19, 2012. Rafael had been with the company since August 2007.